Alarm mechanism



Feb. 12, 1952 JONES 2,585,784-

ALARM MECHANISM Filed May 13, 1950 2 SHEETS-SHEET l I N VEN TOR JUMY 5'. JUN .575

g aBY A TTORNEY J. G. JONES ALARM MECHANISM Feb. 12, 1952 2 SHEETSSHEET 2 Filed May 13, 1950 Patented Feb. 12, 1952 UNITED STATES PATENT OFFICE 2,585,784 ALARM MECHANISM John G. Jones, Rochester, N. Y.

Application May 13, 1950, Serial No. 161,765

Claims. 1

This invention relates to an alarm mechanism, with more particular reference to a structure designed for giving an alarm in the event of a sudden rise in temperature such as precedes or accompanies a fire, and it has for its purpose to afford a portable compact device that is economical to manufacture, practical in operation, and which can be depended upon to give a warning in the event of a fire or quick rise in temperature in the room or zone in which the device is located.

Many disastrous fires have occurred and much loss of life has resulted because occupants of a building have not had suflicient advance warning, and it is a purpose of the invention to prevent such happenings by giving a loud warning signal immediately upon a sudden rise in temperature, so that anyone hearing the alarm will be advised of a potential fire before it has assumed serious proportions.

Various structures have been proposed for creating an alarm upon a sudden rise in temperature, but all such devices have proved impractical or inefiicient due to the fact that they have not been sufficiently sensitive or responsive to temperature changes or depended upon electrical controls, and it is a further object of the invention to afford a construction in which a diaphragm is so sensitive and controlled by the temperature in such a way as to insure operation of the alarm when a sudden rise in temperature occurs and which enables utilizing an alarm operated mechanically, thus avoiding the uncertainty and dif ficulties of electrically controlled mechanism.

It has been proposed to utilize mechanically operated alarms for indicatin a rise'in temperature above a predetermined point, but such devices have not been effective to indicate a sudden rise in temperature as distinguished from a rise above a predetermined point, and it is a particular purpose of the invention to afford mechanical means that will be set in operation as a result of a sudden rise in temperature irrespective of the initial temperature of the room in which the device is located, so that a rise in temperature above apredetermined point will not necessarily sound thealarm and the latter will operate only when a'lgiven rise in temperature takes place in'a'n abnormally short period of time as when a fire bcc r J Another object of the invention is to afford a construction in which an air chamber has a relatively. large area or heat transfer surface that is affected} by the surrounding temperature while the cubicalcontent of the. chamber is small ,in relation, to the-heattransfer, surface, such rel'a-.

2 V tively small body of air within the chamber being expansible sufficiently to effect movement of a very thin and extremely sensitive diaphragm arranged adjacent to an opening 'in a, wall of the chamber and movement of the diaphragm under the influence of the greatly expanded smallbody of air operating to release the alarm operating mechanism.

An additional purpose of the invention is to so construct and mount the diaphragm on the air chamber that an extremely thin and highly sensitive diaphragm can be utilized while insuring its uniform movement and protection against fracture to efiect release of the alarm actuating mechanism.

Still a further object of the invention is to provide a form of detent for releasing the actuating mechanism of such construction that a slight movement of the diaphragm under influence of a sudden temperature change is sufficient to move the detent and release the alarm actuating mechanism.

An additional object of the invention is to af-. ford a detent mechanism and selectively adjustable locking means which when in operative position automatically engages the releasing detent and holds the latter in released position after it is once moved to such position by the diaphragm, so that the alarm continues to ring until the looking means is manually moved to its inoperative position.

Still another purpose of the invention is to afford a spring-controlled alarm actuating mechanism which can be wound by a key and is released by a'detent mechanism that can be arranged for operation by a person walking in proximity to the alarm mechanism, so that the device can be utilized to function as a burglar alarm as -well as a fire alarm, in the event of an unauthorized individual moving in the room or area where the alarm mechanism is located.

To these and other ends, the invention consists in the construction and arrangement of parts that will appear clearly from the following description when read in conjunction with the accompanyin drawings, the novel features being pointed out in the claims following the specification.

In the drawings:

Fig. 1 is a view in side elevation of a portable alarm mechanism constructed in accordance with a preferred embodiment of the invention and showing a cord or thread connected to the detent mechanism, permitting the device to function either as .a fire alarm or burglar alarm;

Fig. 2 is a horizontal sectional view on the line 22 of Fig. 1 looking in the direction indicated;

Fig. 3 is an enlarged detail perspective view showing the releasing detent engaged with the stop member of the actuating mechanism, and the automatic locking dog in operative position ready for locking engagement with the releasing detent when the latter is moved away from the stop member to sound the alarm;

Fig. 4 is an enlarged plan view of the actuating mechanism partially in section with the top shell or bell section removed, and

Fig. is an enlarged vertical sectional view through the top portion of the air chamber and the housing thereabove, with the alarm actuating mechanism inside the housing appearing'in side elevation.

Referring more particularly to the drawings in which like reference numerals refer to the same parts throughout the several views and to Figs. 1 and 5, the air chamber comprises a metal side wall I approximately 5 /2" high, preferably of copper having a thickness of approximately .008" or other thin metal, of corrugated form, as shown in Fig. 2, that is permanently attached by soldering or other suitable means to bottom and top walls 2 and 3. The bottom and top walls 2 and 3 are recessed as shown in Fig. 5 to receive the corrugated side Wall I and to permit attachment thereto by soldering or otherwise so as to maintain apermanent sealed connection between the side wall I and the bottom and top walls 2 and 3, the latter being provided with a central opening 4 through which air moves from inside the chamber when expanding under a quick temperature change. A gradual rise in temperature within the chamber is compensated for by a bleeder opening 5 arranged in the side wall I, permitting the air within the chamber to adjust itself for slow barometric and normal temperature changes without effecting movement of the diaphragm to be described presently.

' The bleeder opening 5 is small, approximately in diameter, which is sufficient to permit the air when expanding slowly from normal temperature changes to pass from the air chamber without affecting the diaphragm and alarm mechanism.

The corrugated side wall I of the air chamber has an outside diameter of approximately l an inside diameter between the innermost limits of the corrugations of approximately 3%" with a 1 s radius forming the inner and outer portions of the corrugations, and an angle of 15 between radii passing centrally through adjacent corrugations, and affords a large heat transfer surface in relation to the cubical contents of the air chamber, thus effecting the necessary expansion of air within the chamber to attain the required movement of the diaphragm, as will be described presently, and it has been found I that satisfactory results are had when there are operation of the detent which releases the actu' ating mechanism.

Owing to thelarge' heat transfer surface of the side wall I of the air chamber and its relatively small cubical content, in case of a quick temperature rise of only a few degrees, the air expands through the opening 4 sufficiently to move the diaphragm through such a distance as to effect operation of the alarm and thus notify anyone within hearing distance of the alarm that there has been a sudden temperature rise and probable fire.

To accomplish this result, there is provided a circular diaphragm 6 of suitable material but preferably metal such as brass, aluminum, or copper. The diaphragm 6 is highly sensitive and very. thin, approximately .0025 in thickness, and is permanently attached around its outer edge to the top wall 3 of the air chamber upon which the diaphragm rests. In order to protect the very thin, delicate and sensitive diaphragm against fracture and to insure its uniform movement, there is provided an aluminum or other circular plate I approximately thick which rests loosely on the central portion of the diaphragm 6 and is guided in a circular opening provided in a surrounding annular plate 8 that is fastened by screws 9 to the top wall 3 of the air chamber, while I0 designates a bottom shell or housing in which the alarm actuating mechanism is mounted the shell I0 being fastened to plate 3 by meansof the screws II. Also secured to the annular plate 8 is a metal supporting frame including uprights I2 and a top horizontal portion I3, see Fig. 5, which supports the spring-wound actuating mechanism in the manner that will now be described.

Secured to the horizontal support I3 is the upper shell or bell housing I4, held in place by a suitable fastening screw I5 provided with a ring I6 by which the device can be conveniently carried, while I! and I8 designate upper and lower plates between which the actuating mechanism is arranged, and which includes a coil spring I9 attached at one end to a post 2I and at its other end to a winding stem 22 which is accessible through an opening 23 of the bell housing I4 to permit placing a removable key on the upper end thereof for winding the spring of the actuating mechanism.

The winding stem 22 carries fixed thereto a ratchet wheel 24 that is engaged and held by a pawl 25 which is pivotally mounted on a gear wheel 26 rotatably surrounding the stem 22, the pawl 25 being held against the ratchet wheel 24 by spring 21.

The gear wheel 26 engages and drives pinion 28 mounted on an arbor 29 which has fixed thereon a gear wheel 3I that engages and drives pinion 32 fixed on shaft 33, that carries an escapement wheel 34 which operates escapement pawl 35 mounted on an oscillatory arbor 36 which carries the arm 31 and striker 38, and thus the striker 38 is actuated by the sprin to engage the bell' housing I4 and sound the alarm Whenever the alarm actuating mechanism is released. The shaft 33 is normally held against movement, and to this end carries a stop member 39 that is arranged for engagement by a detent 4|, see Fig. 3. The detent II normally engages one or the other of the extremities 42 on the stop member 39 and to this end detent 4| is carried by or formed as part of a detent supporting frame including opposite parallel walls 43 and 44 connected by a lateral wall 45 and pivotally mounted on a rod 46 supported on arms 41 which extend downwardly from a'plate 48, the latter "being fixedly mounted on the Fig. 5.

Referring to Fig. 3, the wall 43 of .the detent supporting frame is extended forwardly and provided with a, threaded boss 49 thatreceives an adjustable pin the lower end of the latter being arranged immediately above and in contact with the aforementioned plate 'I which rests on the diaphragm 6, while 52 is acounterweight adjustably secured to the outer end of the wall 43.

With this arrangement, when the diaphragm 6 and plate I are elevated by a sudden temperature rise, the threaded pin 5| is elevated, tilting the detent supporting frame on its axis 46, causing the forward end of wall 43 to move upwardly and the rear end of wall 43, wall 44, and detent 4| to move rearwardly and downwardly, the detent 4| thus moving out of engagement with the stop member 39 and releasing the latter. In this fashion, the alarm actuating mechanism is permitted to operate under the action of the manually wound spring and the striker 38 rings the bell l4 until the temperature is reduced sufiiciently to lower the diaphragm and permit the detent 4| to move back into the path of the stop member 39 under the action of counterweight 52 on the detent frame.

It is desirable to continue sounding the alarm indefinitely after the operation is once initiated by a sudden temperature rise, in order that the occupants will be advised of the danger, and in order to accomplish this, there is provided a lock mechanism that automatically engages and holds the detent in its released position so as to continue operation of the alarm until reset by an attendant, and this is accomplished in the following manner.

Manually adjustable on the plate I8 is a support 53. see Figs. 3 and 5, which is pivoted at 54 and held frictionally in its position of adjustment. The arm 53 is provided with a pair of upstanding lugs 55 between which is pivotally mounted a gravity dog 56, weighted at 51 and thereby held normally in position against, the edge of a lateral extension or lug 58 carried by the wall 44 of the detent frame. Thus when the detent is in normal position holding the stop member 39 against movement, the gravity dog 56 is engaged with the adjacent edge of lug 58, and when the detent frame istilted by the operation of the diaphragm and pin 5|, the lug 58 moves downwardly until it clears the locking gravity dog 56 which thereupon is actuated by its weighted end 51 to swing over the top of lug 58, and thus hold the detent frame and detent 4| out of engagement with the stop member 39.

In this manner, the alarm mechanism' continues in operation until an attendant moves the support 53 and dog 56 away from engagement with the lug 58, thus permitting the detent frame to resume its normal position where it holds the stop member 39 against movement. To enable such adjustment of the locking mechanism and dog 56, the outer lug 55 of the support 53 is provided with a lateral pin 59 which extends through an opening in the lower shell ll) of the housing and is readily accessible for positioning the locking mechanism out of operative positionvwhen it is desirable to stop operation of the alarm actuating mechanism.

It is also desirable to use the mechanism as a burglar alarm to inform when an unauthorized person is moving in proximity to the device, and to accomplish this, there is provided a pin or extension 6|, see Figs. 3 and 5, extending from the wall 44 of the detent supporting frame plate 18 as. shown in' through an opening in the lower shell I0 and provided with an aperture 62 in its outer end while 63 is a post fastened to the base 2. By securing one end of a cord or thread 64 to the post 63 and passing the thread through aperture 62 .in pin 6|, see Fig. 1, the other end of such thread can be fastened to any suitable fixed support in the room, with the thread extending horiset in operating position, the alarm will continue to operate until the lock mechanism is moved out of operative position so as to release the detent frame and permit detent 4| to resume its normal position in the path of the stop member 39.

The operation of the mechanism briefly is as follows: Assuming the detent 4| to be engaged with the stop member 39 and the locking mechanism and dog 56 to be in position for operative engagement with the detent frame, upon a quick rise in temperature and expansion of air through the opening 4, the diaphragm 6 and plate I are elevated, moving the pin 5| upwardly and tilting the detent frame to release detent 4| from engagement with the stop member 39 and sound the alarm. As this operation takes place, the dog 56 engages over the lug 58 and holds the detent frame in such position to permit continued operation of the alarm bell. The same operataion will take place if the thread 64 is engaged by an intruder to pull the pin 6| down wardly and tilt the detent frame. When the temperature surrounding the air chamber has lowered to normal, the-diaphragm 6 and plate 1 will likewise be lowered, but the detent frame cannot return to its normal position until the locking dog 56 has been moved laterally away from lug 53 so as to release the latter and permit it to move upwardly, whereupon the detent frame can tilt on its axis 46 back to normal position with detent 4| in holding engagement with the stop member 39. If the alarm is set 01f by in intruder as already described, the bell will continue to ring until an attendant moves the looking dog 56 away from engagement with the upper surface of the lug 58 to permit return of the detent frame to normal position. After the detent frame has returned to its normal position asshown in Fig. 3, the pin 59 is engaged by the attendant to move the locking dog 56 back to its operative position against the edge of lug 58, where it is again in position to cooperate automatically with lug 58 when the alarm is again set off, either by a quick rise in temperature or by movement of a person into engagement with the thread 64.

While the invention has been described with reference to the particular construction herein disclosed, it is not confined to the details herein set forth, and this application is intended to cover such modifications and departures as may come within the purposes of the improvements and the scope of the following claims.

I claim:

1. In an alarm mechanism operable by a sudden increase in temperature, an air chamber including top and bottom walls and a generally cylindrical thin side wall having vertical cor- 7 chaniberfithe top wall'ihaving an opening therein; a thin'h'igh'ly sensitive circular diaphragm resting upon said top wall at a multiplicity .of radial points and secured around its outer edge to saidtop wall above the aforementioned opening, alarm actuating mechanism arranged above said top wall and diaphragm including a stop member, a detent engaging said stop member, and a pivoted supporting frame on which said detent is fixed, said supporting frame carrying an abutment located in the path of said diaphragm.

2. In an alarm mechanism operable by a sudden increase in temperature, an air chamber including top and bottom walls and a generally cylindrical thin side wall having vertical corrugations and a relatively large heat transfer surface in relation to the cubical content of the chamber; the top wall having an opening therein, a thin highly sensitive circular diaphragm resting upon said top wall at a multiplicity of radial points and secured around its outer edge to said top wall above the aforementioned opening, a circular plate loosely supported on and covering the central portion of said dia- 'phra'gm, guiding means for said plate, alarm actuating mechanism located above the diaphragm and plate including a stop member, a detent engaging said stop member, and a pivoted supporting frame on which said detent is fixed, said supporting frame carrying an abutment located in the path of said diaphragm and plate.

3. In an alarm mechanism operable by a sudden increase in temperature, an air chamber including top and bottom walls and a generally cylindrical thin side wall having vertical corrugations and approximately .008" in thickness having a heat transfer surface of approximately three square inches to each cubic inch of air chamber content, the top wall having an opening therein, a thin highly sensitive circular diaphragm of approximately thickness resting upon said top wall at a multiplicity of radial points and secured around its outer edge to said top wall above the aforementioned opening, a circular plate of approximately a e" thickness loosely supported on and covering the central portion of said diaphragm, guiding means for said plate, alarm actuating mechanism located above the diaphragm and plate including a stop member, a detent engaging the stop member, and a pivoted supporting frame on which said detent is fixed, said supporting frame carrying an abutment located in the path of saiddiaphragm and plate. 7

4. In an alarm mechanism operable by a sudden increase in temperature, an air chamber including top and bottom walls and a generally cylindrical thin side wall having vertical corrugations and a relatively large "heat transfer surface in relation to the cubical content of the chamber, the top Wall having an opening therein, a thin highly sensitive circular diaphragm resting upon said top wall at amultiplicity of radial points and secured around its outer edge to said top wall above the aforementioned openi-ng, alarm actuating mechanism arranged above said top wall and diaphragm including a stop member, a detent engaging said stop member, a pivotedsupporting frame on which said detent is fixed, said supporting frame carrying an abutment located in the path of said diaphragm, and a laterally extending pin connected to said detent permitting attachment of a cord which moves the detent when operated as a burglar alarm.

"5, In an alarm mechanism operable by a sudden increase in temperature, an air chamber including top and bottom walls and a generally cylindrical thin side wall having vertical corruga-tions and a relatively large heat transfer surface in relation to the cubical content of the air chamber, the top wallhaving an opening therein, a thin highly sensitive circular diaphragm resting upon said top wall at a multiplicity of radial points and secured around its outer edge to said top wall above the aforementioned opening, alarm actuating mechanism arranged above said top wall and diaphragm including a stop member, a detent engaging said stop member, a pivoted supporting frame on which said detent is fixed,-said supporting frame carrying an abutment located in the path of said diaphragm, a support quickly adjustable into .and out of operative relation with said detent and held frictionally in adjusted position, and agravity dog carried by said support and movable automatically into locking relation with said detent when the latter moves out of engagement with the aforementioned stop mem- 1 her. 7

JOHN G. JONES.

REFERENCES CITED The'following references are of record in the file of this patent:

UNITED STATES PATENTS 

